This Is The PPT On The Topic Diversity In Living Organism.It Is A Class 9 Biology Chapter.

1. DIVRSITY IN THE LIVING
ORGANISMS
GRADE 9
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8. Whittaker’s System of Classification
It is the five kingdom classification. In the 20th century, advances in cell
biology and interest in evolutionary biology led scientists to question the two
or three-kingdom classification schemes. In 1969, Robert H. Whittaker
proposed a system which recognizes five kingdoms of living things: Monera
(Bacteria), Protista, Fungi, Plantae and Animalia

24. Basis for Animal Kingdom Classification
Classification of Animal Kingdom is based on various fundamental features like –
1.Levels of Organisation,
2.Symmetry,
3.Diploblastic and Triploblastic Organisation,
4.Coelom development,
5.Segmentation of the body and
6.Presense or absence of Notochord.
•The broad classification of Animalia based on common fundamental features:

25. Levels of Organisation
•Though all members of Animalia are multicellular, all of them do not exhibit the same pattern
of organisation of cells.
•For example, in sponges, the cells are arranged as loose cell aggregates, i.e., they
exhibit cellular level of organisation. Some division of labour (activities) occur among the
cells.
•In coelenterates, the arrangement of cells is more complex. Here the cells performing the
same function are arranged into tissues, hence is called tissue level of organisation.
•A still higher level of organisation, i.e., organ level [organ level of organisation] is exhibited
by members of Platyhelminthes and other higher phyla where tissues are grouped together to
form organs, each specialised for a particular function.
•In animals like Annelids, Arthropods, Molluscs, Echinoderms and Chordates, organs have
associated to form functional systems, each system concerned with a specific physiological
function. This pattern is called organ system level of organisation.
•Organ systems in different groups of animals exhibit various patterns of complexities.
•For example, the digestive system in Platyhelminthes (incomplete digestive system) has
only a single opening to the outside of the body that serves as both mouth and anus, and is
hence called incomplete. A complete digestive system has two openings, mouth and anus.
•Similarly, the circulatory system may be of two types: open type in which the blood is
pumped out of the heart and the cells and tissues are directly bathed in it and closed type in
which the blood is circulated through a series of vessels of varying diameters (arteries, veins
and capillaries).

26. Symmetry
•Animals can be categorised on the basis of their symmetry.
•Sponges are mostly asymmetrical, i.e., any plane that passes through the centre
does not divide them into equal halves.
•When any plane passing through the central axis of the body divides the organism
into two identical halves, it is called radial symmetry. Coelenterates, Ctenophores
and Echinoderms have this kind of body plan.
•Animals like Annelids, Arthropods, etc., where the body can be divided into
identical
• left and right halves in only one plane, exhibit bilateral symmetry.

27. Diploblastic and Triploblastic Organisation
•Animals in which the cells are arranged in two embryonic layers,
an external ectoderm and an internal endoderm, are
called diploblastic animals, e.g., Coelenterates.
•An undifferentiated layer, mesoglea, is present in between the ectoderm
and the endoderm. Those animals in which the developing embryo has a
third germinal layer, mesoderm, in between the ectoderm and endoderm,
are called triploblastic animals (platyhelminthes to chordates).

28. Coelom
•Presence or absence of a cavity between the body wall and the gut wall is very important in
classification.
•The body cavity, which is lined by mesoderm is called coelom.
•Animals possessing coelom are called coelomates, e.g., Annelids, Molluscs, Arthropods,
Echinoderms, Hemichordates & Chordates.
•In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present
as scattered pouches in between the ectoderm and endoderm. Such a body cavity is
called pseudocoelom and the animals possessing them are called pseudocoelomates, e.g.,
Aschelminthes.
•The animals in which the body cavity is absent are called acoelomates, e.g., Platyhelminthes.

29. Segmentation
•In some animals, the body is externally
and internally divided into segments with
a serial repetition of at least some
organs.
•For example, in earthworm, the body
shows this pattern called metameric
segmentation and the phenomenon is
known as metamerism.

30. Notochord
•Notochord is a mesodermally [the middle
layer of cells or tissues of an embryo, or the
parts derived from this (e.g. cartilage,
muscles, and bone)] derived rod-like
structure formed on the dorsal side
[posterior] during embryonic development in
some animals.
•Animals with notochord are
called chordates and those animals which
do not form this structure are called non-
chordates, e.g., Porifera to Echinoderms.

52. The scientific naming of an organism is called as nomenclature.
There are different types of naming systems. Most popularly
used naming system is Binomial nomenclature.
Binomial nomenclature, introduced by Carolus Linnaeus is the
method of naming an organism with the genus name first and
species name later.
Conventions followed while writing scientific names
*Name of the genus begins with a capital letter.
*Name of the species should begin with a small letter.
*Scientific name should be in Italics when printed.
*Genus name and the species name should be underlined
separately while handwritten.